1. Field of the Invention
The invention relates to a hydrodynamic torque converter having axial slide bearings.
2. Description of the Related Art
A prior art hydrodynamic torque converter with a converter circuit formed of an impeller, turbine and stator, in which the stator is held by an axial bearing arrangement in the converter housing at a predetermined relative distance from the impeller and turbine is disclosed in German reference DE 195 33 151 A1. In the prior art device, a grooved sliding bearing which can be made of plastic is provided at each axial side of the stator to form the axial bearing. The grooves are constructed such that the individual grooves extend along an entire radial extension of the slide bearing.
A supplied hydraulic fluid flows through the grooves with very low resistance because the grooves extend radially from the inner radial end to the outer radial end of the sliding bearings. Because of the low resistance, the pressure existing in these through-grooves is not always sufficient to ensure hydrodynamic support between the slide bearing and an axially adjacent support structure, such as an impeller hub. This results in a frictional influence. For this reason, these sliding bearings are required to be constructed with high resistance to wear. Further, this prior art construction makes it is possible for hydraulic fluid to flow back into the converter circuit at the sliding bearing between the freewheel and the impeller, which can result in overheating of the torque converter.
The sliding bearings are usually secured to the stator in a positive engagement, such as with a tongue-and-groove connection. Due to the fact, mentioned above, that the hydrodynamic support in these grooves is not always sufficient, axial play may result enabling relative movement in the positive engagement which is perceivable as rattling and can ultimately lead to vibration fracture.